The main and only reason for our existence is to reproduce and make a life for ourselves. Is God necessary?

Simple belief in God is fine.. but then there is man made religion based on man made scriptures.

What does that mean?

When I was about 5 years old I was beginning to wonder 'how did everything come into existence?'?
Then my older brother told me 'God created everything '. 
A simple belief in God was fine and satisfactory for me at that age.  I learned later that belief in God could be helpful in my life and a lot of other stuff..
Eventually I came to believe the scripture writings were inspired by man's belief in God rather than inspired by God. 

What was what your brother told you inspired by?

Probably from school. Was a tradition at our school that the teacher read from the bible each day (about 10 minutes). My family was not very rigiously inclined. 

I get it, thanks K.
As per your question, how do you know that's our only purpose. 

Another purpose for life existence over the billions of years has been to evolve. 
Give another 100,000 or million years and see if there is anything new and improved about the human race -whatever is left of us.

Wish there was some other  purpose than just living making babies then getting old and dying. 
 

The second coming will have been by then... Surely? 

I would actually like for a second coming to happen. 
I just have so much doubt about the existence of God.
He says himself 'thou shalt have no other gods before me'  yet he is allowing Satan to rule the Earth  (as some Christians say so anyway ) why would He do that?

Christianity and Judaism are not the only conceptions of god. 

I believe all cultures have developed belief in spirits or gods. However some like Buddhism determined that a (creator) God does not exist. 

People have waited 2,000 years.  Might be time to admit its unlikelihood.

Life does not come with a purpose. One creates purpose.

That is what I am saying in my question. 

Lago, I would submit that reproduction is the primary intent of all life forms. The question here is a bit of a generalization, because as we all know, we humans are the only species capable of literally "changing the world", though those are independent decisions, not a species-wide imperative. 

If creation was true we never had animal in our lives. 
Religion seems to have done some good but some not so good.
Perhaps people need to learn and practice critical thinking. 

We are mammals. So I guess that makes us animals with certain animal attitudes. Grrrrrrrr!!!

Right. 

Ok I'll look for it at the bookstore.